Conventional guide rails are fixed in position along a conveyor to guide containers as the conveyor moves the containers past the guide rails. For example, the containers may be bottles, boxes or jars into which a product is to be placed, or which are to be further processed (e.g., capping, label application, or packaging), as is well known in the art. Also, the item conveyed may be part of a package, e.g., a cap or closure for a bottle or can. For the purposes of this application, it will be understood that “container” refers to bottles, boxes, jars, cans, and other vessels for holding materials, as well as caps or closures for such vessels. Many different types of conveyors are known, e.g., table-top conveyors, roller conveyors, belt conveyors, beaded conveyors, and air-veyors. Typically, the conveyor moves the container relatively rapidly past the guide rails. Ideally, the guide rails are formed and positioned so that the containers are gently and precisely guided between the guide rails, as is known.
However, the fixed conventional guide rails cannot easily be changed if the shape and/or dimensions of the containers which are to be guided thereby change. In particular, quick vertical adjustment of guide rails is generally not available in the prior art. Adjustable guide rail systems are known, but they have a number of disadvantages. For instance, in one known system, the guide rail is positionable closer to, or further away from, a conveyor in predetermined increments determined by blocks which are insertable to position the guide rail. This arrangement, however, does not provide the flexibility which may be needed, because the guide rails can only be positioned in certain positions, according to the sizes of the blocks. Because the blocks only permit changes in the positions of the guide rails in predetermined increments, this prior art system cannot accommodate all changes in position. Also, in this prior art arrangement, changing the positions of the guide rails is relatively time-consuming.
In another known adjustable guide rail, an adjustment to the guide rail's position is made by using compressed air acting on cylinders, but this prior art system requires that the necessary air pressure be maintained, to hold the guide rail in a required position relative to the conveyor. Also, the ability of this prior art system to accommodate different container sizes is limited.
Because the adjustable guide rails typically are made up of a number of relatively short guide rail portions, each of which is mounted separately on its own support bracket, and because each of the guide rail portions is moved on its support bracket independently of the other guide rail portions, adjusting the known adjustable guide rail systems for different containers tends to be a time-consuming, and sometimes difficult, job.
In some applications, a transition portion is required to be made from a first portion of the conveyor in which only the guide rails on one side are adjustable, to a second portion in which the guide rails on both sides of the conveyor are adjustable (or vice versa). In the first portion, the center line of the bottle (or container) path typically is not coincident with the center line of the conveyor, but in the second portion, the center line of the bottle (or container) path is coincident with the center line of the conveyor. In the transition portion, the guide rails at the ends of the transition portion must be positioned so that they will provide for a smooth transition from the first and second portions. If the positions of the guide rails in the first and second portions are required to change, then the positions of the guide rails in the transition portion are required to be changed accordingly as well. In the prior art, adjustment of the guide rails in the prior art transition portions is time-consuming and difficult, as each guide rail segment in the transition portion is required to be adjusted separately.
It is important that the guide rails be accurately positioned relative to the conveyor, and the containers thereon. For instance, if the containers are not properly positioned by the guide rails, the containers may “shingle”, or jam, frequently. Also, where the containers are guided into equipment in which the containers are processed or acted on (e.g., fillers, or labeling machines), if the containers are not properly positioned, they will not be properly processed. In general, the accuracy of the adjustable guide rail systems of the prior art is not particularly good.